TITLE:   GCN CIRCULAR
NUMBER:  24081
SUBJECT: GRB 190409A: Swift detection of a possible burst
DATE:    19/04/09 14:16:59 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

A. D'Ai (INAF-IASFPA), S. D. Barthelmy (GSFC),
M. G. Bernardini (INAF-OAB), D. N. Burrows (PSU), V. D'Elia (SSDC),
P. A. Evans (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU),
N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL),
K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (PSU),
M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 13:01:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located possible GRB 190409A (trigger=897653).  Swift did not immediately slew
due to an observing constraint.  The BAT on-board calculated location is 
RA, Dec 324.921, -46.607, which is 
   RA(J2000)  =  21h 39m 41s
   Dec(J2000) = -46d 36' 25"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for image triggers, the real-time
light curve does not show anything significant. 

The XRT began observing the field at 13:50:28.1 UT, 2946.9 seconds
after the BAT trigger. No source was detected in 1.2 ks of promptly
downlinked data, which covered 55% of the BAT error circle. We are
waiting for the full dataset to detect and localise the XRT
counterpart. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 2950 seconds after the BAT trigger. No credible afterglow candidate
has been found in the initial data products. Results from the 2.7'x2.7'
sub-image are not available at this time. The 8'x8' region for the list of
sources generated on-board covers 100% of the BAT error circle. The list of
sources is typically complete to about 18 mag. No correction has been made for
the expected extinction corresponding to E(B-V) of 0.02. 

Burst Advocate for this burst is A. D'Ai (antonino.dai AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)